Apparatus for drying sewage-sludge and the like.



APPLICATION FILED MARv 30. 19M.

Patented Sept. 14, L915.

IVER- ogs:

Jomv 3120mm".

WI NESSES:

J. BROMET, FJTHORMAN & H. c. WOOD.

APPARATUS FOR DRYING SEWAGE SLUDGE AND THE LIKE.

APPUCATIO" FILED MAR. 30. I914.

1,153,1 92. Patented Sept'. 14, 1915.

2 SHEETS-SHEET 2.

Laid OWJWAZ.

UNITED STATES. rA'rnN'r OFFICE.

' JonN'BitoMn'r, FRANK THOBMAN,

AND nnNar cLAYroN woon, or rnncasrnn, ENGLAND.

-. arrann'rns non DRYING snwaen-snnnen AND THE To dZ Z whom it may concern Be it. known that we, JOHN Bnorrn'r,

FRANK THORMAN, and HENRY CLAYTON Woo!) subjects of the King of Great Britain and Iireland, residing at Tadcaster, county of York, England, have invented Apparatus for Drying Sewage-Sludge and the like, of which the following is a specification'.

.The'object of ourinvention is to produce that will economically,

sludge or other material contaimng water.

To accomplish this object we em loy one or more rotating cylinders, heated 0th internally and externally,.through which the material to be dried is caused to pass. During this passage-the moisture in the material is evaporated and carried oif by a current of hot a1r circulated through the cylinder or cylinders by means of fans. Dcsm'iption of drawings-Figure 1 1s a sectional elevation (on the line a a of Fig.

. 3) of a drying apparatus according to this invention having two drying cylinders.

Fig. 2 is a cross-sectional elevation of'same (on the line b b of Fig.

3 Fig. 3 is a secgi onal lan of the same on the line 0 c of i 2 ccordin to our said invention, the wet sludge or ot er material to be dried is placed in the hopper A, whence it is continuously and automatically fed into the higher end of the upper cylinder B through a tube 0, by means of a worm D or other suitable appliance. The cylinders B and E are'mounted on-rollers F, and are continuously rotated by suitable gearing G. The cylinders are set on a slight slope, which causes the materialwithin them to be carried forward as they rotate, until it falls from the lower 1 ends of-the cylinders. A chute H is arranged to guide the material as it'falls from the upper'cylinder B into the end of the cylinder E below it. The material is finally discharged in a dried state from the lower end of the bottom cylinder E, through the openingI in. the air box J.

' In the rotating cylinders are placed at intervals, as may be found advantageous, a series of. scrapers, lifting vanes, and teeth, for breaking up the materiaL' K is a fixed scraper, whlch removes any material which ma adhere to the interior surface of the cylinder, and throws it down to the bottom I Specification of Letters latent.

in the Patented Se t. 14, 1915., Application filed March so, 1914. Serial o. 52%,303.

' again. As the material becomes drier,

farther along the cylinder, pegs, or teethL are fixed on the ins1de of the rotating cylinder, which will carry upward any large pieces of material that may be formed.

These pegs orteeth L pass between a num ber of pegs or knives M fastened to a fixed "girder N, thus breaking u carry the material up toward the top and i then drop it down through the current of hot air.

The rotating cylinders are, except at the ends, surrounded by brickwork flues P, and are heated externally by the passing of hot gases of combustion from a furnace through these fiues.

At the same time the interiors of the cylinders, and the material within them, are heated by' hot air circulated through the cylinders by means of a fan.

An air-heater Q is provided for heating the air-which circulates through the cylinders. The air flows around the series of tubes 'R and is heated by conduction from the fur-'- nace gases, which flow throu h the tubes R after issuing from the fiues the cylinders. The source of heat is prefer-, ably a high temperature destructor furnace S with large fire grate, fire brick, arch and lining, and closed ashpit, burning towns refuse, but coal or any other fuel may be.

used.

A circulating fan T maintains a steady flow of air through the cylinders and airheater in a circuit, so that the heated air is brought repeatedly into contact with the wet material and takes up the moisture from it, until the air becomes saturated or nearly so.

The air is delivered from this fan T through the duct U and air-box J into the lower cylinder E. It passes along this cylinder surrounding e and through the air-box V mto and along the upper cylinder B. It leaves the upper cylinder through the air-box W, then passes along-the duct X to the air-heater Q, and from thence it passes back through the duct Y to the suction inlet of the fan T. Or the circulation of the air through the cylinders may be in the reverse direction if desired.

A smaller fan Z is employed to draw off the saturated air from this circuit and discharge it into the chimney, the air thus draw-n off being replaced in the circuit by fresh air from the atmosphere, admitted through the opening I in the air-box J. The saturated air (moist and foul) is drawn as from the circuit by way of two ducts l and 2, which are the only outlets for the foul gases. The portion of the air passing through the duct 1 enters the ashpit 3 (which is otherwise-closed) of the 4 of the furnace, or the fine 5 which is a noxious fumes in the moist air.

continuation of the combustion chamber 4, where it meets the flames and hot gases from the furnace, which. effectually cremate any This ad- I mixture of moist air also serves to reduce the temperature of the furnace gases before they come into, contact with the plates of the drying cylinders. T v v Valves 11 and. 12 are placed in the ducts 1 and 2, by means of which the amounts of air passing through the furnace, and directly entering the-combustion chamber, respectively, can. be varied at will in accordance with the rate of combustion it-is desired to maintain in the furnace. As an alternative arrangement, the duct U may be partly closed by a valve 13 placed'near its outlet into the air-box J, by which means a regulated amount of saturated (foul and moist) air may be forced through the duct 1 or 2, or through both, thus assisting the action of the suction fan Z as described above.

The gases from the furnace and combustion chamber are drawn into the fines 'P surrounding the cylinders through the flue 5,.

After passing along the lengths of the cylinders they are drawn through the flue 6, through the tubes R of the air-heater Q, and along the duct 7 to the suction inlet of the fan Z. This fan delivers the gases through the duct 8 into the chimney 9 and thence into the atmosphere.

Cleaning and inspection doors 10 are provided at suitable points, both for the cylinders and for the fines.

We have found by experience that it is impossible to dry sewage sludge or similar material in a rotating cylinder without thefixed girder, scraper, pegs, etc., as described 1 in this specification W e claim: 1. 'In an apparatus for drying sewage ashpit and through the fire of the furnace or into the combustion chamber, and valves for regulating the amounts of foul air forced.

through the fire of the furnace and discharged into the combustion chamber respectively, so as to reduce the air passing through the fire to the minimum required for combustion, thus obtaining the mostintense heat possible when burning fuel of low calorific value.

' 2. In' an apparatus for drying sewage sludge or other material and in combination, rotating cylinders adapted to receive the material'to be dried, a fan, pipes connecting the cylinders and fan designed to form a circuit through which air is repeatedly circulated, furnace means for externally-heating the cylinders adapted to subsequently heat, on the regenerative principle ,Ithe

air delivered to the cylinders, fan means for withdrawing a portion of the saturated and fourair from the said circuit and forcingit into the ashpit and combustion chamber of the furnace, and means for continuously replacing by fresh air the foul air drawn from the circuit. r

3. In an apparatus for drying sewage sludge or other material and in combination, rotating cylinders adapted to receive the material to be dried, and through which a current of hot air is continuously circulated, furnace means for heating the air, an ashpit under the grate closed to the atmospheric air, means for forcing the hot foul moist air drawn from the hot air circulatingthrough the cylinders into the ashpit beneath the grate, and means for controlling the supply of foul air delivered to the ashpit to regulate the combustion of fuel in the furnace.

4. In an apparatus for drying sewage sludge or other material and in combination, rotating drying cylinders, a fan, a furnace adapted to externally heat the rotatingcylinders and provided with aclosed ashpit,"an air pipe extending between the suction inlet of the fan and the cylinders, pipes leading from the delivery outlet of the fan into the closed ashpit and combustion chamber of the furnace, valves in the said pipes for regulating the amount ofsaturated air discharged into the ashpit .and combustion chamber respectively, and-means for intro- 5. In a drying apparatus for drying sewage sludge or other material andin combination, rotating cylinders adapted to receive the material to be dried, a fixed internal girder extending through one of the cyhnders, a fixed scraper on the girder adapted to remove material adhering to the inner periphery of the cylinder, teeth mounted on the inner periphery of the cylinder, pegs at- 10 tached to the girder adapted to co-act with the teeth as the cylinder revolves, and means for continuously passing hot air through the cylinders to dry the pulverized material, substantially as described.

JOHN BROMET. FRANK THORMAN. HENRY CLAYTON Witnesses:

JOHN E. WALSH,- ALLEN BENNETI'.

' Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, D. G. 

